1. Field of the Invention
Aspects of the present invention relate to a wireless network printing system and method. More particularly, aspects of the present invention relate to a wireless network printing system, in which a wireless terminal connected to an ad-hoc network, and located outside of an access point (referred to hereinafter as an AP) of an infrastructure network, can send data to an image forming device connected to the infrastructure network.
2. Description of the Related Art
Presently, the most commonly used wireless network printing environment is provided by a wireless infrastructure local area network (LAN). Such an infrastructure network includes an access point (AP) to connect a wired LAN and a wireless LAN. A user can print desired data on an image forming device equipped with a wireless network card, and connected to the infrastructure network to a sending device, through the AP.
Another wireless network printing environment is provided by a wireless ad-hoc LAN. In such an ad-hoc network, a wireless terminal can directly (not via an AP) print desired data on an image forming device equipped with a wireless network card, and connected to the ad-hoc network.
Wireless network cards can connect to both the infrastructure network and the ad-hoc network. Therefore, a user can specify and use either the infrastructure network or the ad-hoc network.
The infrastructure network provides a LAN service to a wireless terminal, such as, a personal digital assistant (PDA), or notebook computer equipped with a wireless LAN card, using an AP that corresponds to a hub of a wired LAN. The communication modes of the wireless LAN are classified into an infrastructure mode and an ad-hoc mode. In the infrastructure mode, indirect communication is performed using the wireless LAN card, through the AP, and in the ad-hoc mode direct communication is performed using the wireless LAN card. Therefore, in wireless network printing systems, printing can be performed in both modes.
Generally, the communication of Request To Send (RTS) and Clear To Send (CTS) frames, as defined in the IEEE 802.11 standard, are made in the following order. First, a specific wireless terminal transmits a request to send (RTS) frame to an AP, to ask for permission to commence communication. The AP transmits a clear to send (CTS) frame to permit the communication with the specific wireless terminal, and inhibits communications of wireless terminals other than the specific wireless terminal. The specific wireless terminal transmits data packets (DATA) to the AP, and the other wireless terminals wait for an acknowledgement (ACK) frame. The AP broadcasts the ACK frame upon completion of the data transmission, and a channel contention then occurs again among the wireless terminals. That is, the communication is made in the order of RTS→CTS→DATA→ACK.
A conventional wireless network printing system supports the IEEE 802.11b standard. In this standard, a wireless terminal can perform wireless network printing, within an AP, in the infrastructure mode. The nearer the wireless terminal is to the AP, the higher the data rate is. Also, when the wireless terminal is outside of the AP, it cannot perform wireless network printing. In other words, there is a problem that the wireless network printing can be performed in only a limited area, i.e., within the AP.